mtd: add MEMERASE64 ioctl for >4GiB devices

New MEMERASE/MEMREADOOB/MEMWRITEOOB ioctls are needed in order to support
64-bit offsets into large NAND flash devices.
Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/mtdchar.c

@@ -417,6 +417,7 @@ static int mtd_ioctl(struct inode *inode, struct file *file,
 		break;
 
 	case MEMERASE:
+	case MEMERASE64:
 	{
 		struct erase_info *erase;
 
@@ -427,20 +428,32 @@ static int mtd_ioctl(struct inode *inode, struct file *file,
 		if (!erase)
 			ret = -ENOMEM;
 		else {
-			struct erase_info_user einfo;
-
 			wait_queue_head_t waitq;
 			DECLARE_WAITQUEUE(wait, current);
 
 			init_waitqueue_head(&waitq);
 
-			if (copy_from_user(&einfo, argp,
-				    sizeof(struct erase_info_user))) {
-				kfree(erase);
-				return -EFAULT;
+			if (cmd == MEMERASE64) {
+				struct erase_info_user64 einfo64;
+
+				if (copy_from_user(&einfo64, argp,
+					    sizeof(struct erase_info_user64))) {
+					kfree(erase);
+					return -EFAULT;
+				}
+				erase->addr = einfo64.start;
+				erase->len = einfo64.length;
+			} else {
+				struct erase_info_user einfo32;
+
+				if (copy_from_user(&einfo32, argp,
+					    sizeof(struct erase_info_user))) {
+					kfree(erase);
+					return -EFAULT;
+				}
+				erase->addr = einfo32.start;
+				erase->len = einfo32.length;
 			}
-			erase->addr = einfo.start;
-			erase->len = einfo.length;
 			erase->mtd = mtd;
 			erase->callback = mtdchar_erase_callback;
 			erase->priv = (unsigned long)&waitq;

fs/compat_ioctl.c

@@ -2441,6 +2441,7 @@ COMPATIBLE_IOCTL(MEMGETREGIONCOUNT)
 COMPATIBLE_IOCTL(MEMGETREGIONINFO)
 COMPATIBLE_IOCTL(MEMGETBADBLOCK)
 COMPATIBLE_IOCTL(MEMSETBADBLOCK)
+COMPATIBLE_IOCTL(MEMERASE64)
 /* NBD */
 ULONG_IOCTL(NBD_SET_SOCK)
 ULONG_IOCTL(NBD_SET_BLKSIZE)

include/mtd/mtd-abi.h

@@ -12,6 +12,11 @@ struct erase_info_user {
 	__u32 length;
 };
 
+struct erase_info_user64 {
+	__u64 start;
+	__u64 length;
+};
+
 struct mtd_oob_buf {
 	__u32 start;
 	__u32 length;
@@ -95,6 +100,7 @@ struct otp_info {
 #define ECCGETLAYOUT		_IOR('M', 17, struct nand_ecclayout)
 #define ECCGETSTATS		_IOR('M', 18, struct mtd_ecc_stats)
 #define MTDFILEMODE		_IO('M', 19)
+#define MEMERASE64		_IOW('M', 20, struct erase_info_user64)
 
 /*
  * Obsolete legacy interface. Keep it in order not to break userspace